Demos/USBtoSerial/USBtoSerial.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 #include "USBtoSerial.h"
  32
  33 /* Project Tags, for reading out using the ButtLoad project */
  34 BUTTLOADTAG(ProjName,    "LUFA USB RS232 App");
  35 BUTTLOADTAG(BuildTime,   __TIME__);
  36 BUTTLOADTAG(BuildDate,   __DATE__);
  37 BUTTLOADTAG(LUFAVersion, "LUFA V" LUFA_VERSION_STRING);
  38
  39 /* Scheduler Task List */
  40 TASK_LIST
  41 {
  42         { Task: USB_USBTask          , TaskStatus: TASK_STOP },
  43         { Task: CDC_Task             , TaskStatus: TASK_STOP },
  44 };
  45
  46 /* Globals: */
  47 /** Contains the current baud rate and other settings of the virtual serial port.
  48  *
  49  *  These values are set by the host via a class-specific request, and the physical USART should be reconfigured to match the
  50  *  new settings each time they are changed by the host.
  51  */
  52 CDC_Line_Coding_t LineCoding = { BaudRateBPS: 9600,
  53                                  CharFormat:  OneStopBit,
  54                                  ParityType:  Parity_None,
  55                                  DataBits:    8            };
  56
  57 /** Ring (circular) buffer to hold the RX data - data from the host to the attached device on the serial port. */
  58 RingBuff_t Rx_Buffer;
  59
  60 /** Ring (circular) buffer to hold the TX data - data from the attached device on the serial port to the host. */
  61 RingBuff_t Tx_Buffer;
  62
  63 /** Flag to indicate if the USART is currently transmitting data from the Rx_Buffer circular buffer. */
  64 volatile bool Transmitting = false;
  65
  66 /** Main program entry point. This routine configures the hardware required by the application, then
  67  *  starts the scheduler to run the application tasks.
  68  */
  69 int main(void)
  70 {
  71         /* Disable watchdog if enabled by bootloader/fuses */
  72         MCUSR &= ~(1 << WDRF);
  73         wdt_disable();
  74
  75         /* Disable Clock Division */
  76         SetSystemClockPrescaler(0);
  77
  78         /* Hardware Initialization */
  79         LEDs_Init();
  80         ReconfigureUSART();
  81
  82         /* Ringbuffer Initialization */
  83         Buffer_Initialize(&Rx_Buffer);
  84         Buffer_Initialize(&Tx_Buffer);
  85
  86         /* Indicate USB not ready */
  87         UpdateStatus(Status_USBNotReady);
  88
  89         /* Initialize Scheduler so that it can be used */
  90         Scheduler_Init();
  91
  92         /* Initialize USB Subsystem */
  93         USB_Init();
  94
  95         /* Scheduling - routine never returns, so put this last in the main function */
  96         Scheduler_Start();
  97 }
  98
  99 /** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs and
 100  *  starts the library USB task to begin the enumeration and USB management process.
 101  */
 102 EVENT_HANDLER(USB_Connect)
 103 {
 104         /* Start USB management task */
 105         Scheduler_SetTaskMode(USB_USBTask, TASK_RUN);
 106
 107         /* Indicate USB enumerating */
 108         UpdateStatus(Status_USBEnumerating);
 109 }
 110
 111 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
 112  *  the status LEDs and stops the USB management and CDC management tasks.
 113  */
 114 EVENT_HANDLER(USB_Disconnect)
 115 {
 116         /* Stop running CDC and USB management tasks */
 117         Scheduler_SetTaskMode(CDC_Task, TASK_STOP);
 118         Scheduler_SetTaskMode(USB_USBTask, TASK_STOP);
 119
 120         /* Reset Tx and Rx buffers, device disconnected */
 121         Buffer_Initialize(&Rx_Buffer);
 122         Buffer_Initialize(&Tx_Buffer);
 123
 124         /* Indicate USB not ready */
 125         UpdateStatus(Status_USBNotReady);
 126 }
 127
 128 /** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
 129  *  of the USB device after enumeration - the device endpoints are configured and the CDC management task started.
 130  */
 131 EVENT_HANDLER(USB_ConfigurationChanged)
 132 {
 133         /* Setup CDC Notification, Rx and Tx Endpoints */
 134         Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,
 135                                        ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,
 136                                    ENDPOINT_BANK_SINGLE);
 137
 138         Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,
 139                                        ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,
 140                                    ENDPOINT_BANK_SINGLE);
 141
 142         Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,
 143                                        ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,
 144                                    ENDPOINT_BANK_SINGLE);
 145
 146         /* Indicate USB connected and ready */
 147         UpdateStatus(Status_USBReady);
 148
 149         /* Start CDC task */
 150         Scheduler_SetTaskMode(CDC_Task, TASK_RUN);
 151 }
 152
 153 /** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
 154  *  control requests that are not handled internally by the USB library (including the CDC control commands,
 155  *  which are all issued via the control endpoint), so that they can be handled appropriately for the application.
 156  */
 157 EVENT_HANDLER(USB_UnhandledControlPacket)
 158 {
 159         uint8_t* LineCodingData = (uint8_t*)&LineCoding;
 160
 161         /* Process CDC specific control requests */
 162         switch (bRequest)
 163         {
 164                 case REQ_GetLineEncoding:
 165                         if (bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 166                         {
 167                                 /* Acknowedge the SETUP packet, ready for data transfer */
 168                                 Endpoint_ClearSetupReceived();
 169
 170                                 /* Write the line coding data to the control endpoint */
 171                                 Endpoint_Write_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 172
 173                                 /* Finalize the stream transfer to send the last packet or clear the host abort */
 174                                 Endpoint_ClearSetupOUT();
 175                         }
 176
 177                         break;
 178                 case REQ_SetLineEncoding:
 179                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 180                         {
 181                                 /* Acknowedge the SETUP packet, ready for data transfer */
 182                                 Endpoint_ClearSetupReceived();
 183
 184                                 /* Read the line coding data in from the host into the global struct */
 185                                 Endpoint_Read_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 186
 187                                 /* Finalize the stream transfer to clear the last packet from the host */
 188                                 Endpoint_ClearSetupIN();
 189
 190                                 /* Reconfigure the USART with the new settings */
 191                                 ReconfigureUSART();
 192                         }
 193
 194                         break;
 195                 case REQ_SetControlLineState:
 196                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 197                         {
 198 #if 0
 199                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 200                                          lines. The mask is read in from the wValue parameter, and can be masked against the CONTROL_LINE_OUT_* masks
 201                                          to determine the RTS and DTR line states using the following code:
 202                                 */
 203
 204                                 uint16_t wIndex = Endpoint_Read_Word_LE();
 205
 206                                 // Do something with the given line states in wIndex
 207 #endif
 208
 209                                 /* Acknowedge the SETUP packet, ready for data transfer */
 210                                 Endpoint_ClearSetupReceived();
 211
 212                                 /* Send an empty packet to acknowedge the command */
 213                                 Endpoint_ClearSetupIN();
 214                         }
 215
 216                         break;
 217         }
 218 }
 219
 220 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 221 TASK(CDC_Task)
 222 {
 223         if (USB_IsConnected)
 224         {
 225 #if 0
 226                 /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 227                                  handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 228                 */
 229
 230                 USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 231                         {
 232                                 NotificationType: (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 233                                 Notification:     NOTIF_SerialState,
 234                                 wValue:           0,
 235                                 wIndex:           0,
 236                                 wLength:          sizeof(uint16_t),
 237                         };
 238
 239                 uint16_t LineStateMask;
 240
 241                 // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 242
 243                 Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 244                 Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 245                 Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 246                 Endpoint_ClearCurrentBank();
 247 #endif
 248
 249                 /* Select the Serial Rx Endpoint */
 250                 Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 251
 252                 if (Endpoint_ReadWriteAllowed())
 253                 {
 254                         /* Read the received data endpoint into the transmission buffer */
 255                         while (Endpoint_BytesInEndpoint())
 256                         {
 257                                 /* Wait until the buffer has space for a new character */
 258                                 while (!((BUFF_STATICSIZE - Rx_Buffer.Elements)));
 259
 260                                 /* Store each character from the endpoint */
 261                                 Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 262                         }
 263
 264                         /* Clear the endpoint buffer */
 265                         Endpoint_ClearCurrentBank();
 266                 }
 267
 268                 /* Check if Rx buffer contains data */
 269                 if (Rx_Buffer.Elements)
 270                 {
 271                         /* Initiate the transmission of the buffer contents if USART idle */
 272                         if (!(Transmitting))
 273                         {
 274                                 Transmitting = true;
 275                                 Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 276                         }
 277                 }
 278
 279                 /* Select the Serial Tx Endpoint */
 280                 Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 281
 282                 /* Check if the Tx buffer contains anything to be sent to the host */
 283                 if (Tx_Buffer.Elements)
 284                 {
 285                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 286                         while (!(Endpoint_ReadWriteAllowed()));
 287
 288                         /* Check before sending the data if the endpoint is completely full */
 289                         bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 290
 291                         /* Write the transmission buffer contents to the received data endpoint */
 292                         while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))
 293                           Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 294
 295                         /* Send the data */
 296                         Endpoint_ClearCurrentBank();
 297
 298                         /* If a full endpoint was sent, we need to send an empty packet afterwards to terminate the transfer */
 299                         if (IsFull)
 300                         {
 301                                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 302                                 while (!(Endpoint_ReadWriteAllowed()));
 303
 304                                 /* Send an empty packet to terminate the transfer */
 305                                 Endpoint_ClearCurrentBank();
 306                         }
 307                 }
 308         }
 309 }
 310
 311 /** ISR to handle the USART transmit complete interrupt, fired each time the USART has sent a character. This reloads the USART
 312  *  data register with the next byte from the Rx_Buffer circular buffer if a character is available, or stops the transmission if
 313  *  the buffer is currently empty.
 314  */
 315 ISR(USART1_TX_vect, ISR_BLOCK)
 316 {
 317         /* Send next character if available */
 318         if (Rx_Buffer.Elements)
 319           UDR1 = Buffer_GetElement(&Rx_Buffer);
 320         else
 321           Transmitting = false;
 322 }
 323
 324 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 325  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 326  */
 327 ISR(USART1_RX_vect, ISR_BLOCK)
 328 {
 329         /* Only store received characters if the USB interface is connected */
 330         if (USB_IsConnected)
 331         {
 332                 /* Character received, store it into the buffer */
 333                 Buffer_StoreElement(&Tx_Buffer, UDR1);
 334         }
 335 }
 336
 337 /** Function to manage status updates to the user. This is done via LEDs on the given board, if available, but may be changed to
 338  *  log to a serial port, or anything else that is suitable for status updates.
 339  *
 340  *  \param CurrentStatus  Current status of the system, from the USBtoSerial_StatusCodes_t enum
 341  */
 342 void UpdateStatus(uint8_t CurrentStatus)
 343 {
 344         uint8_t LEDMask = LEDS_NO_LEDS;
 345
 346         /* Set the LED mask to the appropriate LED mask based on the given status code */
 347         switch (CurrentStatus)
 348         {
 349                 case Status_USBNotReady:
 350                         LEDMask = (LEDS_LED1);
 351                         break;
 352                 case Status_USBEnumerating:
 353                         LEDMask = (LEDS_LED1 | LEDS_LED2);
 354                         break;
 355                 case Status_USBReady:
 356                         LEDMask = (LEDS_LED2 | LEDS_LED4);
 357                         break;
 358         }
 359
 360         /* Set the board LEDs to the new LED mask */
 361         LEDs_SetAllLEDs(LEDMask);
 362 }
 363
 364 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 365 void ReconfigureUSART(void)
 366 {
 367         uint8_t ConfigMask = 0;
 368
 369         /* Determine parity - non odd/even parity mode defaults to no parity */
 370         if (LineCoding.ParityType == Parity_Odd)
 371           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 372         else if (LineCoding.ParityType == Parity_Even)
 373           ConfigMask = (1 << UPM11);
 374
 375         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 376         if (LineCoding.CharFormat == TwoStopBits)
 377           ConfigMask |= (1 << USBS1);
 378
 379         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 380         if (LineCoding.DataBits == 6)
 381           ConfigMask |= (1 << UCSZ10);
 382         else if (LineCoding.DataBits == 7)
 383           ConfigMask |= (1 << UCSZ11);
 384         else if (LineCoding.DataBits == 8)
 385           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 386
 387         /* Enable double speed, gives better error percentages at 8MHz */
 388         UCSR1A = (1 << U2X1);
 389
 390         /* Enable transmit and receive modules and interrupts */
 391         UCSR1B = ((1 << TXCIE1) | (1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 392
 393         /* Set the USART mode to the mask generated by the Line Coding options */
 394         UCSR1C = ConfigMask;
 395
 396         /* Set the USART baud rate register to the desired baud rate value */
 397         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineCoding.BaudRateBPS);
 398 }